Katniss, because she actually has realistic emotions; she feels great pain and depression through her journey, and recognizes that she is not a perfect human being. Tris, although having similar qualities, is waaaay to perfect, and it's not realistic.

Katniss. Tris is a wimpy, boy dependent, stereotype inducing, stuck up, poorly written character. KATNISS on the other hand, is completely fine on her own. She is a survivor and has her own set of mind. No matter what comes her way, she doesn't give up